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Aviation History
1969
1969 - 1367.PDF
VSX: Sub-killer for the USN IN A FEW WEEKS' TIME the US Navy will announce the winner of its design competition for a carrier-borne anti submarine warfare aeroplane. VSX. to replace the Grum man S-2 Tracker. Tried and well-proved as the Tracker is, continuous improvement in submarine design — increasing speeds, ranges, operating depths, better armament and counter- measures—all these have begun to make this 1954 design increasingly less effective. Apart from these factors the Tracker is a piston-engined aircraft and in conjunction with turbine- engined aeroplanes requires extra space in the carrier for the storage of inflammable high-octane fuel. The submarine threat is at least as great as any other hazard to national well-being. America is acutely conscious of the 400-plus Russian submarines, many of which are equipped with Polaris-type intermediate-range ballistic missiles. Provid ing an adequate counter is one of the most difficult technical problems of warfare today, and the USN began to consider new ASW designs as long ago as 1962-63. At that time ASW effort was generally in a minor key and it was not until 1967 •that the VSX programme got under way. In November of that year five firms—Douglas, Grumman, McDonnell, Lock heed/LTV and GD—were selected for study contracts. If the problems were difficult, the rewards were correspond ingly high. The entire programme will be worth somewhere between $2 thousand million and S3 thousand million, of which a substantial sum will go towards carrier modification. It is expected that the USN will order between 150 and 300 S-3As (as the project is now known) at a unit cost of some $3 million-$4 million. The value of the aircraft design, develop ment and production contract will probably be well over SI thousand million. . Two firms, GD and Lockheed, were seJected last August to pursue contract definition studies worth about $19 million, and an artists:' impression of the GO submission is illustrated above. This particular design is believed to be fairly typical of others which have been submitted, is similar in shape to the Douglas A-3 Skywarrior, and approximates in size to the Tracker. The moderately swept wing (there is no v.g.) allows a cruising speed of about Mach 0.7, but, at the same time (with high-lift devices) enables good approach and take-off performance. Two engines are housed in under-wing pods, and a frameless cabin allows an excellent view for ASW work for a crew of four: pilot, co-pilot, and two ASW operators. The S-3A will be operated from five E.vspjr-class aircraft carriers. Four of these will at any time be on station, the fifth being in dock for refit. It is probable that these carriers will be stationed in the Pacific. The gradual withdrawal of American bases in this area, both voluntary and as the result of international pressures (the Bonin Islands, which include Iwo Jima, were returned to Japan last year, and the agree ment with Okinawa terminates in 1970) throws increasing emphasis on seaborne patrols. The huge area and distance calls for long range and a performance greatly in advance of its piston-engined predecessor. The S-3A will have an opera tional radius of about 1,000 miles—three times that of the Tracker—and will be able to cruise to the patrol area at 30.000ft-40,OOOft (compared with 6,000ft-7,000ft of the S-2) thereby ensuring greater crew comfort and efficiency. Optimisation of engine parameters for ASW is extremely important. The General Electric TF34-2 was selected over its rival, the P&W TF32, in April last year, and the first engine will run this summer. The TF34-2 is a twin-spool, high-bypass ratio tufbofan of about 9,0001b thrust, designed to give a high thrust/weight ratio and low s.f.c. The S-3A will complement the Orion in protecting the fleet. Its avionics system will be comparable with that of the larger aircraft, but will be miniaturised. As with the RAFs Nimrod, the emphasis is on a much greater degree of auto mation in data processing. Two factors account for this. First the automatic routings of information from the various sen sors: sonobuoy, radar, fume detection and ECM. and second, the provision of a computerised display system in which the various inputs can be "weighed" to provide the most probable fix and track. These techniques considerably off-load the crew which is thus able to give more time to the assessment of data and the planning of the attack. The development schedule calls for the completion of concept-definition studies by next month and the award of a development contract in June leading to first flight 24 months later in June 1971. First flight of the "systems" aeroplane will take place in December of that year, and initial opera tional capability is planned for late 1973.
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